Autor(es): Barroso, Noadia Genuario ; Okuro, Paula Kiyomi ; Martins, Artur ; Pastrana, Lourenço ; Vicente, A. A. ; Cerqueira, Miguel Ângelo ; Cunha, Rosiane Lopes da
Data: 2023
Identificador Persistente: https://hdl.handle.net/1822/98367
Origem: RepositóriUM - Universidade do Minho
Oleogels are semi-solid systems that can function either as replacers of trans and saturated fats and/or as carriers for bioactive compounds. However, interactions and behavior of bioactive compounds when added to oleogels are not fully understood. Thus, the aim of this study was to evaluate the impact of incorporating lipophilic bioactive compounds into oleogel matrices. Sunflower oil was structured with glycerol monostearate (GMS) (2 to 5% w/w) and enriched with -carotene (BC) or resveratrol (R). The gels were characterized by i) rheological measurements using a stress-controlled rheometer; ii) thermal properties by differential scanning calorimeter; iii) microstructure by polarized light microscope and iv) oil binding capacity (OBC) evaluated by accelerated stability tests. Oleogels strength, temperatures associated to sol-gel and gel-sol transitions, as well as crystallization and melting temperatures, were higher with increasing GMS concentration. However, the addition of BC or R did not interfere in the rheological behavior and thermal properties. The microstructure of the oleogel prepared with the lowest GMS concentration (2% w/w) depicted large rosette-like crystals surrounded by small needle-shaped crystals. These structures were unevenly distributed in the crystal lattice, which may be related to their limited oil holding ability (between 50 and 56%). By increasing GMS amount to 5% (w/w) a greater volume of birefringent species and different crystalline morphologies were visualized, improving oil trapping (> 92%). The control system (no bioactive compound added) presented a network composed of needle-like crystals and some regions containing spherulitic crystals. Nevertheless, the addition of bioactive compounds modified the morphology of the larger crystals. Therefore, systems were developed with appealing technological characteristics and an improved nutritional profile. As perspectives, it would be interesting to explore the release of these compounds during digestion and evaluate the oxidative stability of bioactive compound-enriched oleogels.
